1. Field of the Invention
The present invention relates to a communication device that performs a large-capacity data transmission at short range by a weak ultra wideband (UWB) communication mode using a high-frequency broadband, a high-frequency coupler, a coupler electrode, and a composite communication apparatus with a combination of electromagnetic induction type contactless communication and weak UWB communication. In particular, the present invention relates to a communication device that performs large-capacity data transmission and authentication or payment transaction operation associated with data communication by single user's operation so that the user will feel the same sense of access time as that of the typical authentication/payment transaction operation, a high-frequency coupler, a coupler electrode, and a composite communication apparatus.
2. Description of the Related Art
Contactless communications have been widely distributed as media for authentication information, electronic money, and other value information. The contactless communication system is composed of an integrated circuit (IC) chip as a transponder and a device that reads information from the IC chip or writes information to the IC chip (hereinafter referred to as a “reader/writer”). The contactless communication system provides great convenience because the IC chip and the reader/writer therein exchange the information therebetween in a contactless manner. In addition, the IC chip system has been used in the form of a card or incorporated in a personal terminal, such as a cellular phone.
Short-range type IC card standards based on ISO/IEC 14443 include Type A, Type B, and FeliCa (registered trademark). A near field communication (NFC) standard developed by Sony and Philips is an RFID standard that defines the specifications of a NFC device (reader/writer) capable of mainly communicating with each of Type A, Type B, and Felica IC cards. The NFC standard uses the 13.56-MHz band and allows electromagnetic-induction type bidirectional communication with a very short communication range of approximately 0 to 10 cm (“Proximity”).
Recently, a compact size reader/writer module suitable for built-in application has been developed and manufactured. Such a module can be mounted on any of various instruments including Point-Of-Sales (POS) terminals, automatic vending machines, and personal computers (see, for example, http://www.sony.co.jp/Products/felica/pdt/rdw4.html). FIG. 1 is a top view of a modularized reader/writer. As shown in the figure, the reader/writer 101 includes a reader/writer in near field communication (NFC) circuit 102 and an antenna coil 103. FIG. 2 is a cross-sectional view of an apparatus, such a personal computer in which the reader/writer module 101 is housed. In this figure, the structural components of the apparatus are only represented by “internal components” 109 and a “housing” 108 for illustrating in a simple manner. In these figures, the reader/writer module 101 is supported on a metal plate 104 with a ferrite layer 105 through a spacer 106. A communication system based on the NFC standard is a short-range communication with a communication range of approximately 0 to 10 cm, so that the reader/writer module 101 is usually arranged near the surface of the housing 108.
It has become popular to carry out personal identification, electronic money payment, or the like by placing a portable terminal or personal digital assistant (PDA) with an IC card or an IC chip over the reading surface of the reader/writer module in an automatic vending machine, a personal computer, or the like. For instance, there is proposed a note-book type information processing apparatus in which a reader/writer module is incorporated in the palm rest portion of the main body's keyboard to read out information from an adjacent contactless IC tag (see, for example, Japanese Patent Laid-Open No. 2003-87263).
The contactless communication system can be further applied to high-capacity data transmission, such as download or streaming of video, music, or the like. For instance, any fee-based contents can be downloaded from an automatic vending machine into a portable terminal. Alternatively, contents may be downloaded from a fee-based website into the portable terminal through a personal computer connecting to the internet. In this case, the high-capacity data transmission as well as the authentication/payment transaction using the IC chip in the portable terminal can be performed by only a single user's operation of placing the portable terminal over the reading surface of the reader/writer. In addition, an increase in transmission rate is indispensable because of preferably completing the authentication/payment transaction while allowing the user to feel the same sense of access time as that of the typical authentication/payment transaction operation. Moreover, the NFC is an already established technology with respect to authentication/payment transaction operation or the like. Thus, it is preferable to realize high-speed communication while having upper compatibility even at the time of high-capacity data transmission.
The NFC has a transmission rate of approximately 106 to 424 kbps and a sufficient ability to perform authentication or payment transaction, but it is very slow compared with other general-purpose wireless communications (e.g., Wi-Fi and Bluetooth). Therefore, the contactless communication system, such as the NFC system, is hardly applied to high-capacity data communication for transmission of images, sounds, and so on. In addition, the realizable maximum transmission rate of the contactless communication system, such as the NFC system, is up to 848 kbps because of physical restrictions, such as carrier frequency. Thus, a significant increase in transmission rate is not expected.